A 2.34-kg gun has a recoil velocity of 5.2 m/sec. At what velocity does it fire its 95-gram bullets?

Explanation:

We need to use the conservation of energy to help us solve this one.

The energy imparted onto the bullet projectile is equal to the energy imparted into the recoiling gun. We can ignore potential energy and only consider the kinetic energy of the two masses (bullet and gun).

Remember that kinetic energy is expressed as

Conservation of energy means that both the gun and the bullet have the same amount of energy.

We'll want to put the mass terms into the same units. So the gun has a mass of 2340 grams.

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it